I keep the AC off until after startup. For me it's a parts-preservation thing...it is an extra unnecessary load on the engine at startup. The engine cranks harder and longer which puts a strain on parts, particularly the starter.

In the winter, I typically have the heat on when it's warming up. But if I drive it immediately, I'll keep it off until the engine warms up.

I guess that explains why my windshield keeps freezing up when it's on defrost mode, even when it's 80 degrees out (I like the indirect air flow)?

I actually took my temp controls apart the other day trying to get it to stop turning the A/C on when it is turned all the way to cool, but no joy, I couldn't get deep enough into it, and gave it up since I was sweating my ballz off at the time.

Ac with defrost is to remove moisture from the air.
Starting with everything running will not hurt anything. Accesories are disconnected while starting. Notice that the headlights, radio and fan cut off while starting?
Excessive idling will cause some issues (use severe oil change recommendations). As long as you have a 20min drive after the engine reaches normal temp, you shouldn't have any battery issues.
Short trips combimned with excessive idling in winter are battery eaters. Keep idling to 10 min or less.

I keep the AC off until after startup. For me it's a parts-preservation thing...it is an extra unnecessary load on the engine at startup. The engine cranks harder and longer which puts a strain on parts, particularly the starter.

In the winter, I typically have the heat on when it's warming up. But if I drive it immediately, I'll keep it off until the engine warms up.

Ac with defrost is to remove moisture from the air.
Starting with everything running will not hurt anything. Accesories are disconnected while starting. Notice that the headlights, radio and fan cut off while starting?
Excessive idling will cause some issues (use severe oil change recommendations). As long as you have a 20min drive after the engine reaches normal temp, you shouldn't have any battery issues.
Short trips combimned with excessive idling in winter are battery eaters. Keep idling to 10 min or less.

Click to expand...

Agree excessive idling is bad for the engine, but the battery will charge just fine, regardless if you are idling or driving. It will charge more as the rpm's increase though.

I haven't seen this mod, but I'm not sure it's the best idea...kind of defeats the purpose of a defroster. It can't "defrost" if your blowing moist air onto the glass, it probably makes it worse in some conditions.

Yes, this is how the defroster works...the AC dries the air, then the dry air is blown onto the glass picking up the moisture off the glass.

I haven't seen this mod, but I'm not sure it's the best idea...kind of defeats the purpose of a defroster. It can't "defrost" if your blowing moist air onto the glass, it probably makes it worse in some conditions.

Click to expand...

I haven't had the truck long enough to try the defroster in the winter yet, but in the summer it is a pain in the butt because on a warm dry day it actually fogs the windshield up and then the fog freezes unless you turn the heater on or keep running the wipers.
Not liking the A/C linked defroster at all.

Generally most modern vehicles the accessories are disconnected during the actual starter motor running process. So it really should not matter if any A/C, Heat, Radio was on to the battery when you start the car. Now if you tend to sit there for a few minutes and have a questionable battery then you could run it down to where it won't start.